Field of the Invention
The invention relates to an adjustable turbine, in particular to a turbine having a variable flow inlet cross section.
Description of the Related Art
Adjustable turbines are known which have a multiplicity of guide vanes which are pivotable about their own respective axes, such that the turbine wheel can be impinged on by flow in a manner dependent on an available exhaust-gas volume flow rate. Even though very good results can be achieved by this, such turbines with adjustable guide vanes are cumbersome to produce, and accordingly expensive, owing to a high number of parts that move relative to one another.
DE 25 39 711 A1 has disclosed a spiral housing for a turbomachine, in particular an exhaust-gas turbocharger. The spiral housing has a cross section that is adjustable at least in regions. Furthermore, in the spiral housing, a tongue is provided which is guided in sliding fashion and which is displaceable in a circumferential direction and by means of which the spiral inlet cross section can be varied.
It is an object of the present invention to provide an adjustable turbine which is easy to control and which is realized using simple means.